Electronic musical instrument employing free-beam electromechanical resonators and a hand-held baton

ABSTRACT

An electronic musical instrument in which the output of freebeam electromechanical tone generators is coupled from a keyboard to an amplifier by a hand-held baton which is contacted with the keyboard to select the desired tone.

United States Patent [72] Inventor Alvin S. Hopping Nolan 's Point, Lake Hopatcong, NJ. 07849 [21] App1.No. 821,226 [22] Filed May 2, 1969 [45] Patented Nov. 23, 1971 [54] ELECTRONIC MUSICAL INSTRUMENT EMPLOYING FREE-BEAM ELECTROMECIIANICAL RESONATORS AND A HAND-HELD BATON 4 Claims, 14 Drawing Figs.

[52] U.S.Cl 84/1.01, 84/1.05, 84/1.06, 84/l.08, 84/1.15, 84/D1G. 21, 84/D1G. 7 [51] Int. Cl G10h 3/00, G10h 3/08 [50] Field ofSearch 84/1.01, 1.04,1.05,1.06,1.14, 1.15,].07, 1.08

[56] References Cited V UNITED STATES PATENTS 3,546,353 12/1970 Jenny 84/1.01

3,551,579 12/1970 Kramer et a1. 84/1111 3,524,365 8/1970 Jarvis 84/101 1,935,215 11/1933 Severy 84/1.05 X 2,516,579 7/1950 Leonardson.. 84/( D) 2,672,781 3/1954 Miessner 84/1.15 3,115,803 12/1963 Pedicano. 84/1.01 X 3,186,291 6/1965 Pedicano.. 84/1.01 X 3,376,778 4/1968 Musser 84/(D) 3,460,425 8/1969 Kiepe 84/l.01 X FOREIGN PATENTS 646,212 11/1950 Great Britain 84/1.04

Primary Examiner-D. X. Sliney Assistanl Examim'rStan1ey .1. Witkowski AuorneyHerbert Smith Sylvester ABSTRACT: An electronic musical instrument in which the output of free-beam electromechanical tone generators is coupled from a keyboard to an amplifier by a hand-held baton which is contacted with the keyboard to select the desired tone.

ELECTRONIC MUSICAL INSTRUMENT EMPLOYING FREEJIEAM ELECTROMECI'IANICAL RESONATORS AND A HAND-HELD BATON This invention relates to electronic musical instruments. More particularly, it relates to electronic musical instruments utilizing free-beam electromechanical resonators as tone generators. The various features, objects and advantages of the present invention will become apparent on consideration of the following description and drawings, which are merely exemplary.

1 In the drawings:

F IG. 1 is a top view, partially broken away, of a portion of a musical instrument constructed in accordance with the present invention;

FIG. 2 is a view in elevation of the musical instrument of FIG. 1 taken along the line 2-2 of FIG. 1;

FIG. 3 is a schematic representation of the electronic circuitry utilized in the musical instrument of FIGS. 1 and 2, and also illustrates the electrically active components present in an electronic baton which forms part of the instant musical instrument;

FIG. 4 is a side view of a suitable electronic baton construction utilizing the electrical circuitry of FIG. 3;

FIG. 5 illustrates alternative circuitry useful in a version of the baton of FIGS. 3 and 4 modified to include various voicing filters;

FIG. 6 is a side view of a cordless electronic baton (utilizing the circuit of FIG. 7) in operation against a keyboard, which is also shown in partial fragmentary view;

FIG. 7 illustrates details of the contact plate construction used with the baton of FIG. 6, as well as the schematic of suitable associated electrical circuitry;

FIG. 8 illustrates a detail taken along the line 8-8 of FIG. 6 of the supporting structure for the free-beam resonator used in the device of FIG, 6;

FIG. 9 is side views of preferred shapes for the sidewalls of uniform-length free-beam resonators suitable for use in the instant musical instrument;

FIG. 10 shows the beams of FIG. 9 in cross section along the line l0 10 of FIG. 9;

FIG. 11 is a view in elevation of an alternative suitable frecbeam construction;

FIG. 12 is a plan view of the alternative beam construction of FIG. 11;

FIG. 13 illustrates a typical frequency response curve for a beam constructed in accordance with FIGS. 11 and 12; and

FIG. 14 illustrates the modification in the frequency response of the beam of FIGS. 11 and 12 which occurs when load-carrying ears projecting at the ends thereof are bent to redistribute the loads carried thereon to the positions shown by dotted lines in FIG. 12.

Turning now to the embodiment of the figures, which represents an electronic marimba, a generally rectangular instrument case is formed by a top wall 10, a bottom wall 12, and a front wall 14 and rear wall 16 which are made of polished wood.

Disposed along the front edge of the upper surface of the top 10 of the instrument is a series of rectangular conductive metal plates 20-28, which are evenly spaced laterally. These plates are disposed seven to the octave, with five plates being set back in groups of two and three in the conventional piano manner to represent sharps and flats.

Thus, for example, as illustrated in FIG. 1 a contact plate 20 represents the note C, and adjacent contact plates 22 and 24 along the front edge of the instrument represent the musical notes D" and E, respectively. Contact plates 26 and 28 are recessed from the front edge of the instrument, and are disposed between contact plates 20 and 22 and between contact plates 22 and 24 to represent C-sharp and D-sharp, respectively.

Also illustrated in FIGS. 1 and 2 is a free-beam 30 which is formed of sheet steel and supported by two mounting posts 32 and 34. Disposed at the end of the beam adjacent the front of the instrument is a driver coil 40. having a ferromagnetic core 42 which extends from the proximity of the end of the beam 30 upwardly to the proximity of the top 10 of the instrument case.

A regeneration coil 50 is similarly disposed with the bottom of its ferromagnetic core 52 in close proximity to the central portion of the free beam 30, Le, that segment thereof which is disposed between the mounting posts 32 and 34. As is apparent the core 52 of the regeneration coil 50 does not project upwardly as close to the top 10 of the instrument case as does the core 42 of the driver coil 40.

A nonmagnetic support platform 60 runs between the driver coil and the regeneration coil parallel to the top of the instrument case and it carries a permanent magnet 64 and a second permanent magnet 66 which provide fixed magnetic bias for a magnetic circuit which comprises the drive coil 40, the free beam 30, the regeneration coil 50, and the gaps therebetween.

Also carried on the nonmagnetic support platform (but not shown in F IGS. l and 2) are a transistor 70, a resistor 72 and a capacitor 74 which are illustrated schematically in FIG. 3.

As will be apparent from FIG. 3, the driver coil 40, the regeneration coil 50 and the resistor 72 and capacitor 74 are wired to form, in combination with the free-beam resonator 30, an electromechanical oscillator in which the beam is a frequency-determining element. In this system, electromagnetic energy is coupled into the free beam by the driver coil 40 which forms the collector load of the oscillator circuit. An electromagnetic signal is picked up from the free beam by the regeneration coil 50 and applied to the base of the transistor where amplification and regenerative feed back through the driver coil 40 is accomplished. The capacitor 74 and resistor 72 accomplish the appropriate base-leak biasing of the transistor.

As is apparent from contemplation of FIG. 3, operating power is supplied to the transistor oscillator through a conduit 78 leading to the contact plate 20 which is disposed on the top of the instrument case as shown in FIGS. 1 and 2.

Operating power is supplied to the contact plate 20 from a spring contactor 80, which is disposed on the bottom side of a hand-held electronic baton, indicated generally by the reference character 88 in FIGS. 3 and 4.

As also illustrated by FIGS. 3 and 4, the baton 88 is connected through a two-wire cable 90 to a battery 92 which is connected to the spring contactor 80. When the spring contactor 80 engages the contact plate 20, power is applied to the transistor 70 and a tone is generated at the resonant frequency of the beam 30 and associated electronic components.

Also contained within the baton 88 at the projecting end thereof is a pickup coil 99. The lateral spacing between the contact plate 20 and the core 42 of the driver coil 40 is substantially the same as that between the contact point on the spring contactor 80 and the pickup coil 99 in the baton 88, so that when the baton is disposed with its spring contactor 80 in contact with the contact plate 20 on the top of the instrument case, the pickup coil 99 is disposed above the core 42 of the driver coil 40 and in the magnetic field of the driver coil.

The tone signal which is inductively coupled from the driver coil 40 to the pickup coil 99 in the baton 88 is carried through the cable 90 to an amplifier 100, the output of which is delivered to a loudspeaker 102. Such tone signals are so delivered to the amplifier only, however, when the transistor 70 is energized by the delivery of power from the battery 92 through closing of the switch formed by the spring contact 80 and the contact plate 20. The nature and strength of the tone so coupled to the amplifier 100 is determined by the manner in which the end of the baton 88 containing the pickup coil 99 is placed in proximity to the top of the instrument case. Thus, for example, the closer the end of the baton is placed to the instrument case, the louder the tone delivered by the loudspeaker. By the same token, the attack and decay of the note produced may be determined by the rate at which the end of the baton carrying the pickup coil 99 is moved toward or away from the top of the instrument case.

As illustrated in FIG. 5, it is quite feasible to modify the baton of FIG. 4 by incorporating a pushbutton switch 103 into the handle of the electronic baton to permit the optional insertion of appropriate filters to include, for example, a string filter, a horn filter, or a clarinet filter, so that voicing of the instrument can be changed while it is being played.

The baton of FIGS. 3 and 4 requires a connecting cable 90 between the baton and the power source 92 and amplifier 100. An alternative cordless baton construction is illustrated in FIGS. 6 and 7.

The cordless baton 188 of Fig. 6 contains two spring contactors 180 and 182, and a pickup coil 199 disposed on the end thereof. A handle projecting in the opposite direction is also provided.

FIG. 7 shows the modified form of contact plate used with the cordless baton 188. This contact plate has three components. One component is a contact plate 120 mounted flush with the top of the instrument. This plate 120 contacts a leaf spring contactor 182 and, as shown in FIG. 7, is also connected to the input of the amplifier 100.

The terminals of a coupling coil 199 are wired as shown to a second leaf spring contactor 180 which; in use, acts as a switch element to complete a circuit between two conductive segments 183 and I85 forming a split contact plate. One segment 185 of the split contact plate 183-185 is wired to a regeneration coil 150, and the other segment 183 completes the circuit of the regeneration coil to the ground or emitter terminal of the oscillator transistor 170. The driver coil 140 and other components are analogous to those of FIGS. l-4 except as noted.

As illustrated in FIGS. 6 and 8, a resonant free beam 130 is supported by a thin, flexible ribbon 132 which is sufficiently rigid to support the beam 130 and pennit longitudinal vibration thereof while minimizing lateral vibration of the beam. Such support has been found to be quite advantageous in comparison to conventional solid rod supports which exhibit substantial, unifonn rigidity in both of the said directions. Thus, the thin, ribbon supports 132 permit longitudinal beam vibration up to 10 times longer than solid rod supports, thereby permitting the beam 130 to become a rich source of overtones.

FIG. 9 illustrates preferred beam shapes in which sheet steel 0.0l inches thick is used to form beams of substantially uniform length. The beams are varied in cross section in order to provide different resonant frequencies. Thus, the beams are all folded to a U-shaped cross section of substantially uniform length and width, the shape of the depending parallel sides being modified to vary the stiffness of the beams and their natural resonant frequencies. For example, of the three shapes shown in FIG. 9, the beam identified by character reference 200 has relatively wide sections at its center which increases stiffness and imparts a high natural resonant frequency. Beam 202, for midrange notes, may be of uniform side dimensions along its entire length, and beam 204, for lower tones has a thinned midsection which im arts increased flexibility and a lower natural resonant frequency. The cross sections of these beams at their centers is illustrated in FIG. 10.

An alternative suitable methodof tuning beams is illustrated in FIG. 11, in which additional mass, such as a spot of solder 210, may be added to the center of the beam 212 and to flexible ears 220 projecting from the end of each beam 212. The thus-formed beams are very light in weight and very easy to drive with a single transistor in the circuit shown herein.

As shown by FIGS. 13 and 14, the normal resonant frequency of a beam may also be adjusted by bending the solder-carrying projections 220; FIG. 13 representing the response of the beam of FIGS. 11 and 12 in its normal configuration, and FIG. 14 representing the response of the same beam when the flexible ears are bent to the position shown in FIG. 12 by dotted lines.

The present instrument is played using a pair of batons of the type illustrated, one for each hand. The instrument is easy to play and permits solo or two-part harmony with a wide range of voicing, ersonal vibrato automatic vibrato, reverberation and a Wl e control of volume, attack and decay by the manner in which the batons are handled.

What is claimed is:

1. An electrically powered electronic musical instrument which comprises a plurality of electrically powered electromechanical oscillators having free-beam electromechanical resonators for generating musical tone signals, a keyboard, an electromagnetic coupler for the tone signal generated by each of said resonators, said coupler being coordinated and disposed in proximity to said keyboard, a hand-held playing implement to which said musical tone signals are coupled from said coupler when said hand-held playing implement is disposed in proximity thereto, and an amplifier for amplifying said signals coupled to said implement.

2. An electrically powered electronic musical instrument as set forth in claim 1 in which each said electromagnetic coupler is an induction coil which drives each of said free-beam electromechanical resonators and said implement is a baton which contains an inductor which is electromagnetically coupled to said induction coil when said baton is manually disposed in proximity to said keyboard.

3. An electrically powered electronic musical instrument as set forth in claim 1 in which the electromechanical oscillator for generating musical signals is normally inactive and without electric power until supplied with electric power through said keyboard and in which a contact controlling the supply of electric power to said keyboard projects from said baton, electric power being supplied to said keyboard through said projecting contact when the projecting contact on said baton touches said keyboard.

4. An electrically powered electronic musical instrument as set forth in claim 3 in which said induction coil and said inductor are mutually coupled when said baton is disposed such that its projecting contact touches said keyboard. 

1. An electrically powered electronic musical instrument which comprises a plurality of electrically powered electromechanical oscillators having free-beam electromechanical resonators for generating musical tone signals, a keyboard, an electromagnetic coupler for the tone signal generated by each of said resonators, said coupler being coordinated and disposed in proximity to said keyboard, a hand-held playing implement to which said musical tone signals are coupled from said coupler when said hand-held playing implement is disposed in proximity thereto, and an amplifier for amplifying said signals coupled to said implement.
 2. An electrically powered electronic musical instrument as set forth in claim 1 in which each said electromagnetic coupler is an induction coil which drives each of said free-beam electromechanical resonators and said implement is a baton which contains an inductor which is electromagnetically coupled to said induction coil when said baton is manually disposed in proximity to said keyboard.
 3. An electrically powered electronic musical instrument as set forth in claim 1 in which the electromechanical oscillator for generating musical signals is normally inactive and without electric power until supplied with electric power through said keyboard and in which a contact controlling the supply of electric power to said keyboard projects from said baton, electric power being supplied to said keyboard through said projecting contact when the projecting contact on said baton touches said keyboard.
 4. An electrically powered electronic musical instrument as set forth in claim 3 in which said induction coil and said inductor are mutually coupled when said baton is disposed such that its projecting contact touches said keyboard. 